1. Field of the Invention
The present invention relates to an apparatus for producing, and a continuous process for making yarns, in which said yarns are manufactured by processing together a number of singles yarns in such a manner as to result in a final yarn which, when used to manufacture a carpet, floorcovering or textile article, will result in the article having the appearance of being made using a fully twisted face yarn. The present invention additionally relates to yarns made using such a continuous process.
2. Description of Related Art
As used herein, certain terms have the meanings ascribed to them as follows: The terms xe2x80x9cthreadxe2x80x9d and xe2x80x9cfilamentxe2x80x9d are intended to connote single filament fibers, whereas xe2x80x9csingles yarnxe2x80x9d, xe2x80x9csingles fiberxe2x80x9d or xe2x80x9cstrandxe2x80x9d is an assembly of two or more threads or filaments.
Undrawn, essentially unoriented, and partially oriented yarns (POY), melt-spun from thermoplastic polymers provide yarns which are described in the art as xe2x80x9cflatxe2x80x9d, i.e., the filament bundles are essentially linear, and have little shape retention ability or resilience towards deforming forces. As such, these yarns have little utility in the field of carpet manufacture without further processing to improve these properties. A number of processes have been developed over the years in the fiber and carpet industries to provide tufting yarns with increased resilience, bulk, etc., by so-called xe2x80x9cdown-stream processingxe2x80x9d of these yarns. Such processes, which largely consist of physical treatments to the as-spun singles yarns and/or collections of singles yarns brought together to produce higher filament count yarn bundles include, but are not limited to, drawing, (single or multi-stage), texturing, crimping and twisting.
As well as providing yarns with improved physical properties, and carpet backing covering ability, such processes have also been used to provide yarns with a wide range of aesthetic effects. This may be done, for example, by carrying out any or all of the above processes utilising two or more singles yarns in which the said singles yarns differ one from another in terms of dyeability, color, tensile properties, polymer types, cross-sectional shape, denier, or any combination of these. Processes of this type can provide the carpet designer with yarns which may be tufted into backing materials to manufacture carpets of widely ranging design and appearance, which ability would be expected to provide the manufacturer with a commercial advantage in the market-place.
One physical treatment or process which can provide yarns with an aesthetic appearance of particular desirability to the carpet designer is twisting, where singles yarns, particularly of different colors or dyeability, are cable twisted about each other in a spiral fashion. In theory, such a process can be used to provide various degrees of twist interval in the final bundled yarn product, and thus be capable of providing the designer with a number of options for producing a variety of visual effects in the final tufted carpet. However, true cable twisting of carpet denier yarns is difficult, slow and expensive to achieve, and even if achieved, requires that additional materials and processes be used to provide yarns and carpets in which said twist remains stable and unaltered over a period of time.
In order to be able to apply such appearance changes economically to yarns, it would be very useful to have a process which imparts the appearance of true twist to the yarns, without performing an actual cable twist operation. The process would, for economic reasons, be a continuous process, taking a plurality of undrawn, essentially unoriented, or POY singles yarns all the way through to a final, apparent twist, yarn. It would also be preferable to dispense with the need for the use of additional materials or processes in this continuous process, whose sole purpose is to xe2x80x9clockxe2x80x9d the applied twist appearance effect in place and maintain said twist over time either in the yarn and/or in the ultimate carpet application.
Various disclosures have been made of processes proposed for producing xe2x80x9capparent twistxe2x80x9d in carpet yarn, i.e., an appearance of twist, without performing a true twist. None has been commercially successful, whether it be because of technical deficiencies or the inability to process the carpet yarn economically. Several of these are discussed briefly below.
EP 007 563, (Teijin Limited), describes a cut-pile carpet yarn with randomly alternating S and Z false twist, (counter-clockwise and clockwise respectively). Yarn is false twisted in a single direction, heat-set to partially adhere the fiber bundle at node points, and allowed to xe2x80x9cdetwistxe2x80x9d. The last operation, due to the torque inherent in the twisted, heat-set yarn, results in the creation of alternate regions of S and Z twist in the final yarn. Heat-setting techniques, adding an additional step to the process, is required in order to stabilise the shape of the final yarn.
U.S. Pat. No. 3,775,955, (Bigelow-Sanford Inc.), claims an apparatus for the creation of a stable twisted yarn product in which individual singles yarns are simultaneously air-jet spun and twisted, and then combined by entanglement. Use of entanglement as a final process along the total length of the yarn does not result in the appearance effect desired in the present invention.
U.S. Pat. No. 4,051,660, (Akzona Inc.), describes a yarn, and a process for its manufacture, in which two or more previously crimped singles yarns are air jet twisted about each other in totally random S and Z directions. The random twist is present in very short lengths, and does not result in sections of the final yarn having a cable-twisted appearance.
U.S. Pat. No. 4,219,998, (Platt Saco Lowell Ltd.), describes a fluid jet twisting device for twisting strand with alternating S and Z directions. The device has two fluid inlets, and a control system which allows formation of vortices within the device, which, it is claimed will impart alternating twist to a yarn passing therethrough. The device is a stand-alone apparatus, and it is nowhere suggested that it may be used as part of a continuous yarn process starting with undrawn or POY singles yarns, and ending with an apparent twist bundled yarn.
U.S. Pat. No. 4,215,530, (ASA S.A.), is concerned with a process and apparatus in which a POY yarn is subjected to a supplementary, simultaneous drawing and twisting operation. Twist is imparted by a double twist rotating spindle, such that the tension inherent in this part of the process causes the required drawing of the yarn. The yarn is then heat set in an additional process step.
Several patents have issued to E. I. DuPont de Nemours and Company, (U.S. Pat. Nos. 4,873,821; 4,977,739; 5,003,763; 5,012,636; 5,179,827; 5,228,282; 5,465,566; 5,557,915; 5,577,376; 5,598,649; 5,644,909 and 5,829,241), on products, and apparatus and methods for their production, which feature alternate twist plied structures. In general these make alternate S and Z twist plied yarns from individual singles yarns by a process which includes the steps of tensioning the singles yarns as they move in a path through the process, twisting the individual yarns in either an S or Z direction, stopping the twisting operation, then bonding the ply twisted yarns at a node while applying twist, stopping the twisting operation, then repeating the procedure while twisting in the opposite direction. This constitutes a slow and mechanically complex procedure, and requires adhesive, melt, or ultrasonic bonding of the yarns to maintain the twisted configuration.
U.S. Pat. No. 4,949,440, (Belmont Textile Machinery Co., Inc.), describes a process and apparatus in which a previously plied yarn is entangled by an air jet, said air jet travelling with the yarn for a short distance within the entangling device such that the air impinges on only a short section of the yarn. Note that the plied yarn is supplied from a package, and is not passed to the entangling process from a twisting device set within a continuous process.
U.S. Pat. No. 5,263,308, (DuPont), illustrates a high speed ply twisting process utilising the technique known to those skilled in the art as xe2x80x9c2 for 1xe2x80x9d twisting. Use of such a mechanical twisting device is not envisaged in the present invention.
U.S. Pat. No. 5,284,009, (DuPont), exemplifies one solution to the problem, often encountered in the field of twisted yarns, of partial detwisting of the yarn after the twisting torque has been removed. Pile carpet yarns consisting of polyamide or polyester have included therein other fibers of lower melting point, e.g. polyolefins. Ply-twisted yarns of this type may be heat set in a conventional process, during which the polyolefin fibers melt-bond to each other and stabilise the twist in the yarn. This process again uses a heat setting step, and in addition contains extra filaments whose sole purpose is to stabilise the degree of twist imparted to the yarn.
U.S. Pat. No. 5,407,620, (BASF Corporation), describes a process wherein a twisted nylon yarn may be made directly as a continuous process from the melt spinning extruder. Fibers are spun from the extruder spin pack, combined into a yarn and carried through successive heating and cooling zones to a ceramic roller set at an acute angle to the filament path. Passing over said ceramic roller causes twisting of the fiber bundle back into the heating zone from where the twisted yarn passes to the cooling zone where the reduction in temperature is claimed to xe2x80x9cfreeze-inxe2x80x9d the applied twist. The process is thus a continuous spin-draw-twist-setting-winding process. Note, however, that while the ceramic roller may be set to provide yarns with different degrees of twist, and different hands of twist, this cannot be used to alter S to Z twist while the process is running. Also this is a process for the manufacture of twisted singles yarns, and it would appear to be difficult and/or expensive to convert said process into one for dealing with a plurality of extruded singles yarns from a plurality of extruders. Combining already twisted singles yarns into a final yarn would, in any case, result in different yarn appearance to that envisaged in the present invention.
U.S. Pat. No. 5,613,285, (BASF Corporation), is concerned with processes for making multicolor multifilament non-commingled yarns. Two yarns are supplied separately to a drawing process, then to a false twist process together, then to a texturing process. Two of these bundles may then be ply twisted to a final yarn. Note that this method combines the starting singles yarns, and mixed yarns from these, in multiple combining steps throughout the process to provide the final yarn, rather than combining the starting singles yarns together at one point in the continuous process.
Caress Yarns Inc. have two patents, (U.S. Pat. Nos. 5,619,849 and 5,673,549), which describe a method and apparatus for forming a randomly variegated textile yarn by air jet twisting two or more yarns together in a randomly turbulent air device. A traversing drum after said air jet twisting device is set up in such a way as to have random inertial resistance, thereby creating randomly unpredictable take up of the yarn to produce non-uniform random twist in said yarns. While capable of producing final multicolored yarns with novel color effects, this approach does not provide control over the amount or degree of twist, the final product having totally random combination along its length of zero, S and Z twist. At no point either is it claimed that this process can be used as part of a continuous process to manufacture a twisted carpet yarns form a plurality of undrawn or POY singles yarns. In the second of the two patents, the inventor also specifically requires the use of an additional binder yarn spirally wrapped about the twisted yarn bundle.
U.S. Pat. No. 5,706,642, (issued to inventor Jack G. Haselwander), describes a mechanical twisting set-up in which two or more singles yarns may be twisted together in a pre-selected and changeable pattern as set by a programmable controller. The method and apparatus are applicable to any of the known mechanical yarn twisting methods, including cabling, xe2x80x9c2 for 1xe2x80x9d or ring-twisting, all of whose meanings and capabilities are well known to those skilled in the art. With the claimed use of a.c. or servo motors to drive the winders and twisting device, it is unlikely that the twist direction of the yarn could be easily changed from one hand to the other while the machine is running. Neither is it at any point claimed or implied that such a process could be used as a part of a continuous process to manufacture carpet yarns from a plurality of undrawn or POY singles yarns. In any case, such mechanical twisting devices are not envisaged as forming part of the present invention.
U.S. Pat. No. 5,715,584, (BASF Corporation), describes a yarn with a so-called xe2x80x9cpixelxe2x80x9d effect, i.e., the individual singles yarns which go to make up the bundled final yarn substantially retain their identity in the final entangled yarn product and thus their individual colors are visually perceptible. The process whereby this is achieved involves first individually interlacing at least two differently colored or dyeable singles yarns, then combining these together in an entanglement process. While an aesthetically useful yarn is provided in which individual colors are visually perceptible, (unlike the so-called xe2x80x9cheatherxe2x80x9d yarns, where the perceived color is essentially an average of the colors of the singles yarns entangled together to make the final yarn), no twisting process is used, and carpets made using yarns produced via this process show completely different effect in a tufted pile carpet to that seen with true or apparent twist yarns.
U.S. Pat. No. 5,775,087, (Milliken Research Corp.), claims a process in which at least two differently colored singles yarns are separately air jet twisted, either in the same or different hand, then supplied together to a commingling air jet. The final yarn is said to exhibit zero net twist, and no one singles yarn predominates in terms of its color along the length of the product yarn. The process is in fact aimed at eliminating the known problem of xe2x80x9cphasingxe2x80x9d in the manufacture of cut pile plush fabrics, where such combined collage yarns have one component which is occasionally more perceptible than it should be.
U.S. Pat. No. 5,804,115, (BASF Corporation), describes a process in which, directly from the extruder, singles yarns of different colors are independently textured, then combined in an interlacer to yield a final yarn which, it is claimed, can be tufted directly into a carpet, xe2x80x9cwithout further texturing or twistingxe2x80x9d. Practice of this invention results in a so-called xe2x80x9cmock space-dyedxe2x80x9d yarn. By this is meant a yarn made from different color singles yarns in which one color may predominate for random moderate lengths of said yarn and which, in visual appearance and in a carpet construction gives an effect similar to a true space-dyed yarn. Space-dyed yarns are those produced in a process of dyeing a white dyeable yarn in such a way that the color thereof varies randomly along the length of the yarn. The approach in this invention does not involve twisting of the yarn, nor does it provide the same aesthetic effects as are possible with a true or apparent twist yarn.
U.S. Pat. No. 6,023,926, (DuPont), is another patent claiming a method for the manufacture of a carpet yarn which simulates the appearance of a space-dyed yarn. The so-called xe2x80x9cstyling yarnxe2x80x9d of the invention consists of two or more differently colored yarns false-twisted together, with a wrapper yarn spirally wound about this core yarn. False twist may be imparted to the core yarn by either a rotating hollow spindle apparatus, such as those commercially available from Suessen of Germany, or by an alternate twist ply jet as described in U.S. Pat. No. 5,179,827, (DuPont), referred to previously. It is stated in this document that there is no actual twist and substantially no intermingling between the singles yarns of the core, but rather a slight amount of false twist therebetween. This slight amount of false twist in the core results in low frequency alternation of the predominant color perceived in the final yarn along the length of said final yarn. Thus the product has the color attributes of a space-dyed yarn rather than a twisted yarn, both as a yarn, and in a carpet tufted therewith. The process and product also has the added complexity of requiring the wrapper yarn, whose sole function is to maintain the imparted configuration of the final yarn.
U.S. Pat. No. 6,052,983, (Belmont Textile Machinery Co., Inc.), claims an apparatus for inserting twist into a moving strand, said apparatus consisting of an assembly of units, each supplied with compressed air and having air channels therein communicating with the channel containing the said moving strand, set to direct air tangentially to the moving yarn in order to impart twist thereto. The number, size, and relative configuration of said units making up said apparatus may be varied in order to account for alteration of S and Z directions of twist, degree of twist, and yarn size. Production of twisted yarns via the apparatus claimed is achieved by inserting alternate S and Z directions of false twist into the singles yarns used to manufacture the final yarn, and stabilising said twist by xe2x80x9ctackingxe2x80x9d the twisted singles yarns via known methods, e.g., an air jet entangler. The inherent twist in the singles yarns results in spontaneous plying together of these yarns into a final yarn as they are brought into juxtaposition. Note that, in the case of this invention, the individual singles yarns are twisted before they are allowed to spontaneously ply together at a later stage in the process. It is also nowhere stated or implied that this apparatus could be used as part of a continuous process for the manufacture of apparent twist yarns from a plurality of undrawn or POY singles yarns.
Consideration of the extensive prior art summarised above has led to the conclusion that there still exists a need in the field of face yarns for use in tufted carpets, particularly loop-pile carpets, for a simple, economical process which would allow the in-line continuous manufacture of apparent twist yarns from a plurality of undrawn or POY singles feed yarns. Such a process would ideally eliminate the need for the use of slow mechanical twisting devices, would not require an expensive heat-setting stage, and would dispense with the use of fibers, besides the differently colored or dyeable singles yarns, whose sole purpose is to stabilise the twist imparted to the final product yarn.
In the course of extensive experimental study of methods of achieving apparent twist yarns, the inventors have discovered a process which meets the above criteria.
The present invention is concerned with a process for the manufacture of an apparent twist yarn for use in carpets, especially loop-pile tufted carpets, floorcoverings and textile articles. By xe2x80x9capparent twistxe2x80x9d is meant a yarn which has the appearance, at least for major sections of its length, of being composed of two or more singles fibers or yarns, at least one of which is of a different color or dyeability to the others, which are spirally wound one about the other with a relatively tight spiral, giving a xe2x80x9cbarber-polexe2x80x9d like appearance. In said process, a plurality of undrawn or partially oriented, (POY), continuous filament singles yarns, at least one of which is of a different color or dyeability to the others are passed through the following sequence of treatments:
a) Drawing of each singles yarn separately and simultaneously;
b) Mechanical crimping of said drawn singles yarns;
c) Entangling of said drawn and crimped singles yarns separately and simultaneously;
d) Converging of said individually drawn, crimped and entangled singles yarns, and passing of the yarn bundle thus created through an air jet entangler and a pair of twist jets;
e) Conveying of stabilised apparent twist yarn to a take-up station.
The air jet entangler, also termed a bundle entangling jet, is designed such that the passageway through the body of the entangler through which the yarn bundle travels increases in cross-sectional dimension along the direction of travel of the yarn bundle. The two twisting jets are set up so as to impinge tangentially on the yarn bundle from opposite sides, thus imparting alternate regions of S and Z twist to the said yarn bundle. The aforementioned design of the bundle entangling jet will tend to retard the advancement of the bundle to the twisting jets, thereby imparting a tension on the strand, in addition to entangling the bundle. The tensioning of the yarn is believed to aid in making the twist being imparted by the twist jets of a more permanent character, thus eliminating the need for further processing steps in order to accomplish this twist permanence. This results in the production of a yarn with stable regions of alternating twist.
The present invention is further concerned with apparent twist yarns made via the above process.